App-11
IM DLM3054-01EN
Appendix 4 TCP and UDP Port Numbers
The TCP and UDP port numbers that are used on the Ethernet interface of the instrument are listed below.
TCP Port Numbers
Port Number Description
Used For
20
File Transfer [Default Data]
FTP server, FTP client*
21
File Transfer [Control]
FTP server, FTP client
25
Simple Mail Transfer Protocol
SMTP client
515
−
LPR client
111
−
Instrument control through the Ethernet interface
1024
−
1025
−
UDP Port Numbers
Port Number Description
Used For
67
Bootstrap Protocol Server
DHCP client
68
Bootstrap Protocol Client
(listen port)
111
−
Instrument control through the Ethernet interface
123
Network Time Protocol
SNTP client
* The port number when FTP passive mode is disabled. When FTP passive mode is enabled, you can set any
port number. When FTP passive mode is disabled, connections are established from the server. If you are
connecting the instrument from behind a firewall, enable FTP passive mode.
Appendix